/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.qrcode.view;

import com.tigerfire.iot.R;
import com.google.zxing.ResultPoint;
import com.google.zxing.qrcode.camera.CameraManager;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

import java.util.Collection;
import java.util.HashSet;

/**
 * This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial transparency outside
 * it, as well as the laser scanner animation and result points.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class ViewfinderView extends View
{
    
    private static final int[] SCANNER_ALPHA = {0, 64, 128, 192, 255, 192, 128, 64};
    
    private static final long ANIMATION_DELAY = 100L;
    
    private static final int OPAQUE = 0xFF;
    
    private final Paint paint;
    
    private Bitmap resultBitmap;
    
    private final int maskColor;
    
    private final int resultColor;
    
    private final int frameColor;
    
    private final int laserColor;
    
    private final int resultPointColor;
    
    private int scannerAlpha;
    
    private Collection<ResultPoint> possibleResultPoints;
    
    private Collection<ResultPoint> lastPossibleResultPoints;
    
    // This constructor is used when the class is built from an XML resource.
    public ViewfinderView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        
        // Initialize these once for performance rather than calling them every time in onDraw().
        paint = new Paint();
        Resources resources = getResources();
        maskColor = resources.getColor(R.color.esp_qrcode_viewfinder_mask);
        resultColor = resources.getColor(R.color.esp_qrcode_result_view);
        frameColor = resources.getColor(R.color.esp_qrcode_viewfinder_frame);
        laserColor = resources.getColor(R.color.esp_qrcode_viewfinder_laser);
        resultPointColor = resources.getColor(R.color.esp_qrcode_possible_result_points);
        scannerAlpha = 0;
        possibleResultPoints = new HashSet<ResultPoint>(5);
    }
    
    @Override
    public void onDraw(Canvas canvas)
    {
        Rect frame = CameraManager.get().getFramingRect();
        if (frame == null)
        {
            return;
        }
        int width = canvas.getWidth();
        int height = canvas.getHeight();
        
        // Draw the exterior (i.e. outside the framing rect) darkened
        paint.setColor(resultBitmap != null ? resultColor : maskColor);
        canvas.drawRect(0, 0, width, frame.top, paint);
        canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
        canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
        canvas.drawRect(0, frame.bottom + 1, width, height, paint);
        
        if (resultBitmap != null)
        {
            // Draw the opaque result bitmap over the scanning rectangle
            paint.setAlpha(OPAQUE);
            canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
        }
        else
        {
            
            // Draw a two pixel solid black border inside the framing rect
            paint.setColor(frameColor);
            canvas.drawRect(frame.left, frame.top, frame.right + 1, frame.top + 2, paint);
            canvas.drawRect(frame.left, frame.top + 2, frame.left + 2, frame.bottom - 1, paint);
            canvas.drawRect(frame.right - 1, frame.top, frame.right + 1, frame.bottom - 1, paint);
            canvas.drawRect(frame.left, frame.bottom - 1, frame.right + 1, frame.bottom + 1, paint);
            
            // Draw a red "laser scanner" line through the middle to show decoding is active
            paint.setColor(laserColor);
            paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
            scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
            int middle = frame.height() / 2 + frame.top;
            canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);
            
            Collection<ResultPoint> currentPossible = possibleResultPoints;
            Collection<ResultPoint> currentLast = lastPossibleResultPoints;
            if (currentPossible.isEmpty())
            {
                lastPossibleResultPoints = null;
            }
            else
            {
                possibleResultPoints.clear();
                lastPossibleResultPoints = currentPossible;
                paint.setAlpha(OPAQUE);
                paint.setColor(resultPointColor);
                for (ResultPoint point : currentPossible)
                {
                    canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 6.0f, paint);
                }
            }
            if (currentLast != null)
            {
                paint.setAlpha(OPAQUE / 2);
                paint.setColor(resultPointColor);
                for (ResultPoint point : currentLast)
                {
                    canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 3.0f, paint);
                }
            }
            
            // Request another update at the animation interval, but only repaint the laser line,
            // not the entire viewfinder mask.
            postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom);
        }
    }
    
    public void drawViewfinder()
    {
        resultBitmap = null;
        invalidate();
    }
    
    /**
     * Draw a bitmap with the result points highlighted instead of the live scanning display.
     * 
     * @param barcode An image of the decoded barcode.
     */
    public void drawResultBitmap(Bitmap barcode)
    {
        resultBitmap = barcode;
        invalidate();
    }
    
    public void addPossibleResultPoint(ResultPoint point)
    {
        possibleResultPoints.add(point);
    }
    
}
